共查询到20条相似文献,搜索用时 93 毫秒
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格子Boltzmann方法中的曲边界处理 总被引:4,自引:2,他引:2
研究了格子Boltzmann方法中实现曲边界条件的3种格式,对它们的精度和稳定性进行了分析和比较.通过二维Poiseuille流和等边三角域上空腔流的模拟,讨论了这3种格式的数值精度和稳定性. 相似文献
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在大型固体激光器结构稳定性设计中,数值模拟结果是结构稳定性设计的主要依据,故数值模拟的可信度至关重要。为了评估装置稳定性计算结果的可信度,基于现代模型验证与确认技术中关于不确定性源的量化及传播分析方法、模型形式误差与预测推断的叠加方法研究,对靶球结构的最大位移响应进行了预测推断。稳定性分析中为了快速进行不确定性参数的传播和灵敏度分析,使用二次响应面模型作为代理模型,灵敏度分析结果表明模态阻尼比对靶球结构的稳定性影响更大。对关心量的稳定性预测结果表明,靶球结构最大位移响应的上界与稳定性设计指标相比,安全裕度仍大于7,说明主机装置的稳定性设计具有足够的可信度。 相似文献
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求解烧蚀面附近流场的定常解,并以此作为基本流实现用高精度的WENO格式对烧蚀瑞利-泰勒不稳定性的数值模拟.线性增长率与Lindl公式以及线性稳定性分析给出的结果相符合,证明该数值模拟方法的准确性与精度,该方法还具有较好的界面变形捕捉能力. 相似文献
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Mustafa Inc Abdullahi Yusuf Aliyu Isa Aliyu Dumitru Baleanu 《Optical and Quantum Electronics》2018,50(4):190
This research presents soliton solutions and stability analysis to some conformable nonlinear partial differential equations (CNPDEs). The CNPDEs equations in this paper are conformable Cahn–Allen and conformable Zoomeron equations. The powerful sine-Gordon method is used to carry out the soliton solutions for these equations. The aspects of stability analysis for the considered equations is investigated using the linear stability technique. The sine-Gordon method proves to be efficient and effective for the extraction of soliton solutions for different types of CNPDEs. 相似文献
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The influence of a Lorentz violation on soliton solutions generated by a system of two coupled scalar fields is investigated. Lorentz violation is induced by a fixed tensor coefficient that couples the two fields. The Bogomol’nyi method is applied and first-order differential equations are obtained whose solutions minimize the energy and are also solutions of the equations of motion. The analysis of the solutions in phase space shows how the stability is modified with the Lorentz violation. It is shown explicitly that the solutions preserve linear stability despite the presence of Lorentz violation. Considering Lorentz violation as a small perturbation, an analytical method is employed to yield analytical solutions. 相似文献
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Peter van Heijster Arjen Doelman Tasso J. Kaper 《Physica D: Nonlinear Phenomena》2008,237(24):3335-3368
In this article, we analyze the stability and the associated bifurcations of several types of pulse solutions in a singularly perturbed three-component reaction-diffusion equation that has its origin as a model for gas discharge dynamics. Due to the richness and complexity of the dynamics generated by this model, it has in recent years become a paradigm model for the study of pulse interactions. A mathematical analysis of pulse interactions is based on detailed information on the existence and stability of isolated pulse solutions. The existence of these isolated pulse solutions is established in previous work. Here, the pulse solutions are studied by an Evans function associated to the linearized stability problem. Evans functions for stability problems in singularly perturbed reaction-diffusion models can be decomposed into a fast and a slow component, and their zeroes can be determined explicitly by the NLEP method. In the context of the present model, we have extended the NLEP method so that it can be applied to multi-pulse and multi-front solutions of singularly perturbed reaction-diffusion equations with more than one slow component. The brunt of this article is devoted to the analysis of the stability characteristics and the bifurcations of the pulse solutions. Our methods enable us to obtain explicit, analytical information on the various types of bifurcations, such as saddle-node bifurcations, Hopf bifurcations in which breathing pulse solutions are created, and bifurcations into travelling pulse solutions, which can be both subcritical and supercritical. 相似文献
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In this paper, a method sustaining system stability after decomposition is proposed. Based on the stability criterion derived from the energy function, a set of intelligent controllers is synthesized which is used to maintain the stability
of the system. The sustainable stability problem can be reformulated as a Linear Matrix Inequalities (LMI) problem. The key to guaranteeing the stability of the system as a whole is to find a common symmetrically positive definite matrix for
all subsystems. Furthermore, the Evolved Bat Algorithm (EBA) is employed to replace the pole assignment method and the conventional mathematical methods for solving the LMI. The EBA is utilized to find feasible solutions in terms of the energy equation. The experimental results show that the EBA is capable of providing proper solutions, which satisfy the sustainability and stability criteria, after a short period of recursive computing. 相似文献
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C. Schmidt-Hattenberger R. Muschall U. Trutschel F. Lederer 《Optical and Quantum Electronics》1992,24(6):691-701
For a nonlinear three-core fibre coupler an important subclass of solutions has been investigated analytically. These are the stationary solutions or nonlinear eigenmodes. Their stability is checked using an exact method as well as the linear perturbation method, and numerical tests. 相似文献
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Adzhit Kumar 《Russian Physics Journal》1979,22(9):948-951
Using the direct Lyapunov method for distributed systems, the problem of stability of particlelike solutions of the equation of a scalar field with logarithmic nolinearity is solved. It is shown that nonlinearities of the Heaviside function type, which ensure the existence of exact regular solutions for the Klein-Gordon equation, are not a very fruitful approach because of the mathematical difficulties encountered in studying the stability of such solutions.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 29–33, September, 1979. 相似文献
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Solutions to the equations describing materials with competing quadratic and cubic nonlinearities
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The Lie group theoretical method is used to study the equations
describing materials with competing quadratic and cubic
nonlinearities. The equations share some of the nice properties of
soliton equations. From the elliptic functions expansion method, we
obtain large families of analytical solutions, in special cases, we
have the periodic, kink and solitary solutions of the equations.
Furthermore, we investigate the stability of these solutions under
the perturbation of amplitude noises by numerical simulation. 相似文献
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A.Y.T. Leung 《Journal of sound and vibration》2008,309(3-5):718-729
The spectral dynamic stiffness method using exact solutions of the governing equations as shape functions has been popular for vibration and dynamic stability analyses of framed structures consisting of uniform members. Since non-uniform members do not generally have closed form solutions, special cases only have been considered. However, exact solutions are still possible for generally non-uniform members using power series. The paper studies the exact dynamic stability of columns with distributed axial force by power series. Both uniform and distributed, compression and tension, and conservative and non-conservative axial forces are considered. Interaction diagrams of various kinds of axial loads on the natural frequencies including different intensities of the distributed loads and degree of tangency are given. Follower tension buckling is reported for the first time. It is found that the power series outperforms the dynamic stiffness method in terms of versatility in applications and numerical stability at the very low and high ends of the frequency spectrum. 相似文献
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Drumi Bainov Zdzisław Kamont Emil Minchev 《International Journal of Theoretical Physics》1994,33(6):1359-1370
Theorems on stability and asymptotic stability of solutions of impulsive partial differential equations of first order are proved. These results are obtained via the method of differential inequalities and via the method of Lyapunov functions. 相似文献
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The stability and bifurcation analyses of periodic motions in a rotating blade subject to a torsional excitation are investigated. For high speed rotations, cubic geometric nonlinearity and gyroscopic effects of the rotating blade are considered. From the Galerkin method, the partial differential equation of the nonlinear rotating blade is simplified to the ordinary differential equations, and periodic motions and stability of the rotating blade are studied by the generalized harmonic balance method. The analytical and numerical results of periodic solutions are compared. The rich dynamics and co-existing periodic solutions of the nonlinear rotating blades are investigated. 相似文献